[Help-smalltalk] Which Class do I use?

[Duke Normandin]

Or more specifically, "How does one *start* an OOP/GST program?

My understanding so far of OOP - which, to me, means GST - is that
there exists the following general structure:

Genesis Object (God)
|
+--ClassA  (which is an object having its origin in God)
|      |
|      + ---- ClassA.InstanceOf1 (which is an object)
|      |               |
|      |               +--feature1 (which is an object)
|      |               |
|      |               +--message1 (that feature1 understands)
|      |               |
|      |               +--feature2
|      |               |
|      |               +--message2
|      |
|      |
|      +---- ClassA.InstanceOf2
|
+--ClassB
|
+--ClassC
|
and the list goes on, and on, and on, and on... ;)

Am I "on track" at all, so far?

So, when a person begins to design an OOP/GST program/script, with
what Class do you start? Let say that I want to create a console app -
say a text-based calculator (which eventually I'll migrate to
ncurses). The app will (pseudo-code) do the following:

print-to-screen "Duke's Kick-ass GNU-Smalltalk Calculator"
skip a line
print-to-screen "Select a math Operation [+ - * /]:
wait for user input, then inhale it
print-to-screen "Enter first operand":

You get the idea!

What Class do I use to start the Inheritance ball rolling? String?
Math? Is there a "template" type of thing to organize the OOP design?

In C - which I know very little of - you have the general structure:

prototypes go here
global vars go here

blah main()
{
local vars go here
Opening statement goes here
etc
etc
}

other functions go here

I probably don't have the C program structure dead on, but you get the
point I hope. So far, my impression of OOP/Smalltalk classes is that
they're like Perl's CPAN modules repository - is that correct?

I'm using the a couple of GST tutorials to get me started with the
syntax etc, but I'm still not clear on how to start "thinking in OOP"
- obviously.
-- 
duke